The direct determination of free acrylonitrile in aqueous copolymer latices. Part I. Rapid potentiometric titration method

Abstract

A rapid semi-automatic procedure for the direct determination of 0-05 to 15 per cent. of acrylonitrile monomer directly in aqueous butadieneacrylonitrile latices is described. The determination is carried out without prior separation of the monomer and is based on the addition reaction of sulphite and acrylonitrile and subsequent potentiometric titration of the liberated alkali to a pre-set pH end-point.Results reproducible to within f2 per cent. relative are obtained on latex samples containing 15 per cent. of monomer, and with samples containing only 0.1 per cent. of free acrylonitrile the reproducibility is still within f 15 per cent. relative.

Rubber

“…A byproduct of the addition reaction is Na-OH, which is titrated with HC1. Results were accurate to 2% relative at the 15% level and to 15% relative at the 0.1% level (199). The parameter measured was changed to temperature rise when the sample and reagent were mixed in a continuous flow cell.…”

Spectrophotometric determination of acrylonitrile

“…Stock solutions of acrylonitrile were made by pipetting approximately 0.5 mL into a tared 100-mL volumetric flask containing 25 to 50 mL of distilled water, and reweighing to obtain the weight of acrylonitrile. In order to ensure the accuracy of weighing and the purity of the acrylonitrile, the titration method reported by R. P. Taubinger (4) was used to analyze the stock solutions.…”